Having read Leroy Thompson's article on the tactical mirror sight in the Oct. 2008 SWAT magazine, I see that I was beatened to the design. The idea isn't original to me and Union soldiers did something similar during the Civil War. From Sam Watkin's book, Company Aytch:

Quote:

“The Yankees would hold up small looking glasses, so that our strength and breastworks could be seen in the reflection in the glass; and they also had small mirrors on the butts of their guns, so arranged that they could sight up the barrels of their guns by looking through these glasses, while they themselves would not be exposed to our fire, and they kept up this continual firing day and night, whether they could see us or not.”